Heart valve disease continues to be a significant cause of morbidity and mortality, resulting from a number of ailments including rheumatic fever and birth defects. Recent statistics show that valvular heart disease is responsible for nearly 20,000 deaths each year in the United States, and is a contributing factor in approximately 42,000 deaths. Currently, the primary treatment of aortic valve disease is valve replacement. Worldwide, there are approximately 300,000 heart valve replacement surgeries performed annually.
Coronary artery disease also remains a leading cause of morbidity and mortality and manifests in a number of ways. For example, disease of the coronary arteries can lead to insufficient blood flow resulting in the discomfort and risks of angina and ischemia. In severe cases, acute blockage of coronary blood flow can result in myocardial infarction, leading to immediate death or damage to the myocardial tissue.
A number of interventional approaches have been developed for treating heart valve and coronary artery disease. For instance, annuloplasty rings have been developed in various shapes and configurations over the years to correct mitral regurgitation and other conditions which reduce the functioning of the valve. Heart valve replacement may be indicated when there is a narrowing of a native heart valve, commonly referred to as stenosis, or when the native valve leaks or regurgitates, such as when the leaflets are calcified. When replacing the valve, the native valve may be excised and replaced with either a biologic or a mechanical valve. Coronary blockage can often be treated endovascularly using techniques such as balloon angioplasty, atherectomy, or stents.
Most interventional techniques are conducted under general anesthesia and require that the patient's sternum be opened and the chest be spread apart to provide access to the heart. The first 2-3 days following surgery are spent in an intensive care unit where heart functions can be closely monitored. The average hospital stay is between 1 to 2 weeks, with several more weeks to months required for complete recovery. While often very effective, the use of open-heart surgery to perform cardiac procedures is a highly traumatic to the patient.
Recently, minimally invasive surgical techniques and procedures to perform coronary artery bypass grafting (CABG) and other traditionally open-chest cardiac surgical procedures are gaining acceptance. A wide variety of laparoscopic, arthroscopic, endovascular, and other surgical therapies have been developed. These procedures generally utilize trocars, cannulas, catheters, or other tubular sheaths to provide an artificial lumen, through which specialized tools are inserted and manipulated by the surgeon.
Some researchers propose implanting prosthetic heart valves at the aortic annulus using a direct-access transapical (through the left ventricular apex) approach (e.g., U.S. Patent Publication No. 2006-0074484). The left ventricular apex LVA is directed downward, forward, and to the left (from the perspective of the patient). The apex typically lies behind the fifth left intercostal space (or between the fourth and fifth), 8 to 9 cm from the mid-sternal line, and about 4 cm below and 2 mm to the medial side of the left mammary papilla. Access to the left ventricle may therefore be attained through an intercostal incision positioned over the fifth left intercostal space. Such an approach is often termed a “mini-thoracotomy,” and lends itself to surgical operations on the heart carried out using one or more short tubes or “ports”—thus, the operations are often referred to as “port-access” procedures.
Dehdashtian in U.S. Patent Publication No. 2007-0112422 discloses a port-access delivery system for transapical delivery of a prosthetic heart valve including a balloon catheter having a steering mechanism thereon that passes through an access device such as an introducer. The surgeon forms a puncture in the apex with a needle, advances a guidewire, then a dilator, and finally the introducer. Edwards Lifesciences sells the Sapien™ Heart Valve that may be inserted transapically with the Ascendra™ delivery system, much like the system disclosed in Dehdashtian.
Often, direct- or port-access techniques are conducted or proposed for off-pump, or beating heart procedures. The advantages of eliminating open-heart procedures and cardiopulmonary bypass are evident. Challenges remain in retracting and stabilizing tissue, and in providing improved visualization, during these procedures. During port-access procedures, it can be helpful for a retractor to create an opening through which surgeons can not only advance medical devices but which also provide a visualization area of sufficient size. Many current retractors provide retraction in only two opposing directions, which can limit the size of the opening provided. Other retractors have radiopacity that prevents a surgeon from seeing the desired field of view beyond the retractor via x-ray or similar techniques. An additional issue is the need to hold medical devices during a procedure. For example, during ring or valve replacement, the ring and/or valve is often secured to a handle for delivery through the access port. During the procedure, this handle is typically held within the access port at a desired position by a second operator who assists the main surgeon conducting the procedure. The surgeon typically takes needle and suture one at a time and goes around the ring/valve perimeter in order to secure the ring/valve within the native valve annulus.
During many surgeries, such as valve surgeries, there is a need for a retractor that can create an opening through which surgeons can operate, which may include retraction of bone as well as soft tissues. In some cases there is also a need for the retractor to create a sufficient visualization area for the surgeon to visualize the operating area within the patient. Some current retractors retract the tissue in limited directions which can limit the size of the opening created (thus limiting the access and/or visualization). Other retractors have may have excessively radiopaque materials that may prevent x-ray visualization of the field of view beyond the radiopaque retractor.
Another potential issue during surgeries such as heart valve repair (e.g., valve ring deployment) and/or heart valve replacement procedures is the number of personnel required to conduct the procedure. For example, in a valve ring or prosthetic valve deployment, the valve ring or prosthetic valve is typically secured to a handle that must be held in place while the main surgeon stitches (e.g., with needle and suture passing around the valve/ring perimeter to secure the prosthetic in place) or otherwise secures the valve ring/prosthetic valve in its desired position in the patient. Typically a second operator is required to hold the valve ring/prosthetic valve in place via the handle during the stitching process.
There is a need for improved retractors capable of creating a port opening with improved visualization while eliminating the need for a second operator to hold the handle of the deployment device. The current invention satisfies these needs.